Process for the manufacture of sulphates of ammonia



Patented Aug. 13, 1935 rnooess Adrianus V v erlands, assignor,

Shell Development AMMONIA Nethmesne assignments to .San Francisco,

Calif a corporation of Delaware H No Drawing. No. 490,822. a r 2 Claims.

1 My'invention relates to the manufacture of sulphates of ammonia e. g.ammonium sulphate or ammonium .bisulphate, by subjecting gaseousconversion of ammonium sulphite into ammoitor instance niumsulphate,which latter substance is a valuable constituent of artificial manure. f

a igeneralthese processes consist in treating a solution or ammoniumsulphite with oxygen or air or with other oxidizing gases, sothataromtion of ammonium sulphate is formed, which thereafter isconcentrated in orderto separate out the ammonium sulphate m solid form.

H .Attemptshave been made to oxidize am monium sulphite in solid form bytreating it with oxygen-"- containing gases, but the yield of ammoniumsulcphate has been relatively small.

".Ihave now found that the oxidation or compounds containing thecomponents NHs and S02, ammonium "sulphite or ammonium bisulphite,whether in the solid phase for in aqueous solutions, isconsiderablyimproved'if the oxidation is performedwith the aid of-oxygenor oxygen-containing gases in the presence of one or more nitrogenoxidesyor substances which yield nitrogen oxides under the conditions ofthe process. For the purpose of this invention the term nitrogen oxideis to be regarded as exclud- :ing nitrous oxide. i r

I have also found that the manufacture of sulphatesoi ammonia directiromgaseous ammonia, sulphur dioxide, water or water vapour and oxidizinggases, is considerably facilitated by the presence of said nitrogenoxide'or oxides of other substances yielding these oxides under 'thecon- .ditions oi the reaction. i

"I .havefound, that the last mentioned method advantageously be carriedout by conducting gaseous ammonia, sulphur'dioxide and oxidizing gasesinto water; Y a According to the invention, the oxidation is preferablycarried out at "an elevated temperature, in the presence or absence ofsubstances promoting the desired oxidationl Sometimesit 'is advantageousto perform the reaction at increased or at reduced pressure. 1 i Asoxidizing gases, air or oxygen or other oxyg en-cantaininggases or gasmixtures may be employed. 1 x The initial materials as well as thenitrogen oxides may be of any-convenient origin.

Application In Great Britain-October 2 (or. "ea-119) October 23, 1930,Serial The nitrogen oxides should preferabl be mixed with theoxygen-containing gases before they come into contact with thesubstances 'or mixtures of substances tobe oxidized. The oxidation ofsolid ammonium 'sulphite or other solidcompounds containing thecomponents N113 and 502, such as ammonium bisulphite, may be readilycarried out, according to the invention, by passing a mixture of air andnitrogen peroxide through the substance to be oxidized, which isintroduced into a tubeheated to a' temperature of, for example 80 C.Inorder to promote 'efiicient contact between the oxidizing medium andthe substance to be oxidized the latter ,may be stirred -or kept movingin any *The outflowi'g gases, if. necessary, enriched withsoxygen andnitrogen peroxide,'maybe again conducted through a fresh quantity ofsubstance to beoxidized. I

Advantageously the mass to be oxidized may be treated several times withthe nitrogen peroxide-containing oxidizin'g medium, in "order to convertthe total quantity of ammonium sulphite into ammonium sulphate;

As stated above. the nitrogen oxides or the substances which yieldnitrogen oxides under the conditions of the reaction also catalyze thereaction between ammonium sulphite or ammonium bisulphite in aqueoussolutions and oxygen or oxygen-containing gases.

An aqueous solution of ammoniu 'sulphite or ammonium bisulphite may beadvantageously prepared by introducing roastgases, which be sidessulphur dioxidecontain a large percentage "ofnitrogen originating fromthe air used for the oxidation into water, whilst gaseous ammonia iss'imultaneouslyblown' into the water. The nitrogen escapes from thesolution without carrying along with it the ammonium sulphite, as is thecase when preparing ammonium sulphite sulphite *solution obtained inthis way can into a solution of ammonium sulphate with the aid of oxygenor oxygen-containing gases and in the presence of nitrogen oxides.

' As mentionedabove, it isalso possible to periorm the oxidation of theammonium sulphite simultaneously with its formation.

The following examples illustrate how the process "of the invention maybe carried into effect:

" I UNITED STATES PATENT oiF EliCiE} 2,011,301f ron 'rn'n MANUFAc'rUacoFiii -l.- 40 gra "s'oi a mixture of 77.8 parts ofammonium sulphi'te and22.2 parts of ammonium sulphate is brou ht into a tube. During one and ahalf hours and at a 'ten'iperature of C. N02- treated in this manner wasfound to obtain 18.3% the like, whereafter the contact substance is reofsulphite and 81.7% of sulphate. generated with hydrogen, causing thesulphur to On subjecting the treated mass to a second combine with thehydrogen and thereby forming 5 oxidation the 'total conversion of thesulphite sulphuretted hydrogen. The latter may then be into sulphate canbe effected. oxidized in thepresence of a catalyst, whereby 2. Equalvolumes of sulphur dioxide and amsulphur dioxide mixed with other gasesor vamonia are introduced into 2.5 litres of Water until pours is formedwhich mixture may be used dia 10% ammonium bisulphite solution has beenrectly for the manufacture of ammonium sul- 10 oxide and ammonia in thesame proportions by monia, Water vapour and sulphur di xi m y 15 arerepeated until the desired concentration of with the sulphur dioxide.The air may also be ammonium bisulphateis attained, blown in at the endpoint of the passage of the An important advantage of theabove-mensulphate in the apparatus, from which point it is tioned mannerof carrying out the process of the forced in a direction opposite tothat of the stream invention is that the oxidation capacity, calcuof heother mp n n s. The ni ro en oxide 35 paratus per day, is much greaterthan that of it is particularly advantageous to carry out the Asexamples of substances which, in the desmall amount of nitrous vapoursas catalyst into 30 scribed solutions, yield nitrogen oxides, the saltsa Concentrated um lph u n of nitrohydroxylam mc a id may b e ti d, 4. 5litres of pure water are introduced into WhlCh salts, when treated withm neral d a suitable reaction vessel filled with so-called give nitricoxid 1 Raschig-rings. Thereafter air, sulphur dioxide 3. Ammonia,sulphur dioxide, water and air containing 5% by volume of nitric oxide(NO), 5 mixed with nitric oxide, are simultaneously inand ammonia areintroduced into the water sep tro-duced into a vessel, the interior ofwhich is a at y ut simultan u ly. Th v l city with kept at approximately80 c T elocity th which the sulphur dioxide is introduced amounts whichthe gaseous ammonia is introduced approximately to 300 p m u th of the pamounts to approximately 4 litres per minute, mm n a o a pr ma y 600 s.p mmut 49 litres per minute and that of the air mixed with an EXCESS ofsulphur d x de is present throughout.

Simultaneously, approximately 2 cubic centi- R hi -rin s constitute awell-known and metres of water per minute are introduced in a widelyusedfilling material for Washingw rs, 45 finely divided st t reactionchambers, fractionation columns, etc.

The product of the reaction is removed from The Outer diameter o therings is pp x m the apparatus in a continuous manner. It is qu to hheight s o 25 mm. h h are composed of nearly pure ammonium sulphate,most y employed). Raschig-r ngs a e en al y which may be converted into100% ammoniu made of metals, e. g; iron, but also rings of sulphate bytreating it with air mixed with nitric Ceramic material a e b n used.

oxide at a temperature of approximately 80 C. The t p atur of the lut ongradually in- Hitherto the manufacture of ammonium sul-- r a o appr ximaly 60 0., which has a phate by oxidation in the gaseous phase couldfavourable eiTect on the conversion velocity only be effected by makingspecial provisions and From the gases Withdrawn h ni r n x des 55 It isan important advantage of the present ture thereof, that even in anammoniacal medium ly overcome. taken place. The following experimentsillus- The reacting components may, if necessary or trate this feature.

desirable, be employed in diluted condition, i. e. 5. To cc of asolution containin 7 pours, such as may be obtained by variousprocrespect to free ammonia. Into this solution .70 with other gases.Thus, for example, sulphurtrogen peroxide is introduced at a velocity of36 containing gases or vapours, such as coke gas, or litres per hour andat a temperature of 60 C. sulphur-containing mineral oils or productsAfter 40 minutes the quantity of the unoxidized (1775 therefrom, may bedesulphuriz'ed in known mansulphite was found to amount to only 0.0068gram ,75

L 6. To 100 molecules. As the 24 litres of oxygen introduced into thesolution contained 30 cc. of N02, the quantity of sulphite oxidized permolecule of N02 is 136 molecules.

cc. of an ammonium sulphite solution containing 0.1741 gram molecules ofcombined S02, 10 cc. of 0.5 normal sulphuric acid are added. Thereafteroxygen, cent by volume of N02, is passed through the solution at atemperatureof 60 C. and at a 1 velocity of 36 litres per hour. After 35minutes only 0.0026 gram molecules of S02 remainedunoxidized. The 21litres of oxygen, introduced into the solution contained 26 cc. of N02,the

l5 quantity of sulphite oxidized per molecule of N02 being 1 60molecules. What I claim is:

containing per 1. Process for the manufacture of sulfates of ammoniacomprising forming a 10% ammonium bi-sulphite solution sulfur dioxideinto water, introducing an airnitric oxide mixture wherebya desiredconcentration of ammonium sulfates is formed.

ammonia comprising forming a 10% solution of ammonium bi-sulfate inwater, thereafter introducing an air-nitric oxide. gas mixture into saidsolution whereby sulfates of ammonia. are formed.

ADRIANUS JOHANNES VAN PESKI.

d aira t .io 2. Process for. the manufacture of sulfates of-

